Civil Engineering Reference
In-Depth Information
Fig. 11.3. This keyed drill chuck has a shank that can be held in a collet. It is ideal for
small drills up to 4mm. It can be fed into the work by hand feeding the knurled wheel
into the job.
CENTRE DRILLS
You are likely to come across many different types of drill in the home work-
shop. We will start with the two types of centre drill.
Slocombe centre drills
The Slocombe centre drill comes in various diameters, with the body usually
starting at
1
⁄
8
in diameter with a small pilot on the centre. The
1
⁄
8
in size can be
obtained with various different pilot diameters. You can also get centre drills
in larger sizes such as
1
⁄
4
in,
5
⁄
16
in,
3
⁄
8
in and
1
⁄
2
in. (Metric centre drills are also
now available.)
